Browsing by Author "Huang, Joseph Jen-Tse"

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Biocompatible Inhibitor Based on Chitosan and Amphiphilic Peptide against Mutant Huntingtin Toxicity
(1970-01-01)
Wahyuningtyas, Devi
;
Chen, Wen-Hao
;
Huang, Chen-Han
;
He, Yu-Jung
;
Huang, Joseph Jen-Tse
Huntington's disease (HD) is classified as a protein-misfolding disease correlated with the mutant Huntingtin (mHtt) protein with abnormally expanded polyglutamine (polyQ) domains. Because no effective drugs have yet been reported, attempts to develop better therapy to delay the age of onset are in urgent demand. In this study, an amphiphilic peptide consisting of negatively charged hexaglutamic acid and a stretch of decaglutamine (E(6)Q(10)) was chemically synthesized as an inhibitor against polyQ and mHtt toxicity. It is found that E(6)Q(10) selfassembles into spherical vesicles, as shown by means of TEM, cryoelectron microscopy, and dynamic light scattering. Assembled E(6)Q(10) prevented the polyQ-rich peptide (KKWQ(20)AKK) from forming amyloid fibrils. To enable the cell-penetration ability of E(6)Q(10), the E(6)Q(10).chitosan complex was generated. It is demonstrated that the complex penetrates cells, interferes with the mHtt oligomerization and aggregation process, and prevents mHtt cytotoxicity. By combining positively charged chitosan and amphiphilic peptides with a negatively charge moiety, a new strategy is provided to develop biocompatible and biodegradable inhibitors against mHtt toxicity.
Photocontrollable Probe Spatiotemporally Induces Neurotoxic Fibrillar Aggregates and Impairs Nucleocytoplasmic Trafficking
(2017-07-01)
He, Ruei-Yu
;
Chao, Shu-Han
;
Tsai, Yu-Ju
;
Lee, Chi-Chang
;
Yu, Chu-Yi
The abnormal assembly of misfolded proteins into neurotoxic aggregates is the hallmark associated with neurodegenerative diseases. Herein, we establish a photocontrollable platform to trigger amyloidogenesis to recapitulate the pathogenesis of amyotrophic lateral sclerosis (ALS) by applying a chemically engineered probe as a "switch" in live cells. This probe is composed of an amyloidogenic peptide from TDP-43, a photolabile linker, a polycationic sequence both to mask amyloidogenicity and for cell penetration, and a fluorophore for visualization. The photocontrollable probe can self-assemble into a spherical vesicle but rapidly develops massive nanofibrils with amyloid properties upon photo activation. The photoinduced in vitro fibrillization process is characterized by biophysical techniques. In cellular experiments, this cell-penetrable vesicle was retained in the cytoplasm, seeded the mislocalized endogenous TDP-43 into aggregates upon irradiation, and consequently initiated apoptosis. In addition, this photocontrollable vesicle interfered with nucleocytoplasmic protein transport and triggered cortical neuron degeneration. Our developed strategy provides in vitro and in vivo spatiotemporal control of neurotoxic fibrillar aggregate formation, which can be readily applied in the studies of protein misfolding, aggregation-induced protein mislocalization, and amyloid-induced pathogenesis in different diseases.